Device for checking corporal functions

ABSTRACT

A monitoring device comprising an oscilloscope having three inputs connected to three switching members. The first switching member receives signal voltages corresponding to the monitored parameters, whereas the second and third switching members receive upper and lower limit voltages of the signal voltages. The oscilloscope is scanned horizontally and vertically. The signal voltages and the limit voltages are sequentially scanned during each horizontal trace period and are compared with a sawtooth voltage synchronized with the vertical scan of the oscilloscope to produce control pulses that are applied to the oscilloscope beam control grid to intensity modulate same to simultaneously display the signal and limit voltages.

atet [191 Kuipers et al.

DEVICE FOR CHECKING CORPORAL FUNCTIONS Inventors: Pieter Geert Kuipers;Jan Albert Meerdink, both of Emmasingel,

Eindhoven, Netherlands Assignee: U.S. Philips Corporation, New

York, NY.

Filed: Feb. 17, 1969 Appl. No.: 799,620

Foreign Application Priority Data Feb. 16, 1968 Netherlands 6802208 U.S.Cl 340/150, 324/121, 340/213 R Int. Cl G08b 23/00, G01r 13/20 Field ofSearch 340/213 R, 324 R, 324 A,

References Cited UNITED STATES PATENTS OTHER PUBLICATIONS InformationDisplay, Challenges for Display". Arthur L. Aden Nov./Dec. 1967. pp.32-34.

Bet 340/324.1 UX Lauher 340/32-1-.l UX

Primary Examiner-Donald J. Yusko Attorney. Agent, or FirmFrank R.Trifari 5 7 ABSTRACT A monitoring device comprising an oscilloscopehaving three inputs connected to three switching members. The firstswitching member receives signal voltages corresponding to the monitoredparameters, whereas the second and third switching members receive upperand lower limit voltages of the signal voltages. The oscilloscope isscanned horizontally and vertically. The signal voltages and the limitvoltages are sequentially scanned during each horizontal trace periodand are compared with a sawtooth voltage synchronized with the verticalscan of the oscilloscope to produce control pulses that are applied tothe oscilloscope beam control grid to intensity modulate same tosimultaneously display the signal and limit voltages.

10 Claims, 2 Drawing Figures INVENTORS PIETER G. KUIPERS BY JAN A.MEERDINK AQEN;

PAIENTEDM 1 9 I974 II... I

IIIII/lrrll l DEVICE FOR CHECKING i: t

FUNCTIONS This invention relates to a system for monitoring a pluralityof parameters and displaying the monitored information on the screen ofa cathode ray tube.

For checking corporal functions in carrying out medical examinations,increasing use is being made of devices by means of which electricalderivations of such functions are measured and can be visibly displayedin usable units. It is often desirable that a number of such devicesoperate simultaneously, such as, for example, for taking anelectrocardiogram and for measuring the blood pressure and the flow rateof blood, the temperature and the frequency of respiration and of thepulse wave. In certain cases, for example, for post-operation patientobservation it is particularly important that the indications providedby the devices can easily be surveyed and can simultaneously be observedwithout the observer changing his position for this purpose.

An object of this physiological observation is not only to displaydynamic and analog magnitudes, but also to notice the occurrence ofabnormal conditions. Derivations from periodically changing phenomenaare usually applied to an oscilloscope so that the variation can beobserved on the screen of a cathode-ray tube. The electrocardiogram andthe variation of the pulse wave are displayed in this manner.

The analog signals are derived from functions chang ing only slowly, ina certain rhythm, or arbitrarily. Usually such signals are visiblydisplayed by means of dial instruments which may be provided withadjustable alarm contact pointers for adjusting limit values.

The ability to survey the overall indications in a quick manner isadversely influenced when using dial instruments because it is necessaryto sit comparatively close to the instruments for observation andbecause a concentrated visual adjustment to each separate instrument isnecessary for reading a meter indication on a graduated scale.

For simultaneously and visibly displaying different measuring voltageson the display screen of a cathoderay tube, cathode-ray oscilloscopesare furthermore in use which are provided with a corresponding number ofinputs for applying a number of measuring voltages. Due to a certainarray of the signals on the screen of the cathode-ray tube, a clearsurvey may be obtained but then voltage values which mostly deviate fromthe applied measuring voltages, although proportional thereto, must bederived in order to render such an array possible. The displayed signalsthen show the voltage variation, but only a relative judgement withrespect to the measured value is possible. The introduction of limitvalues for judgement results in this case in a further extension of thenumber of inputs by two inputs for each measuring value so that such adevice becomes very voluminous and costly.

An object of the invention is to obviate these drawbacks by providing adevice for displaying physiological measuring voltages, a number ofwhich are displayed on the screen of a cathode-ray tube and theexamination of which is enhanced, due to a logic array, it also beingpossible to indicate limit values in a simple manner for each measuringvoltage separately. According to the invention the device is providedwith an oscilloscope including a cathode-ray tube operating inaccordance with the vertical scanning principle and comprising at leastone input which is connected to a number of switching members whichsuccessively connect the input to a number of measuring voltages duringmutually equal periods. The switching members remain in the conditionassociated with the measured voltage so that each measuring voltage isconnected once to the relevant input during the horizontal scanningperiod of the cathode-ray tube.

When using a two-channel oscilloscope the invention provides thepossibility to display a dynamic signal and a succession of analogsignals on areas of the screen of the cathode-ray tube separated fromtop to bottom. In the series of analog signals each signal isrepresented as a short horizontal line. These lines are connectedtogether by rising or falling connection lines so that the overallsignal has the form of a step-like curve in which the height of a stepcorresponds to the height of the associated measuring voltage to beindicated. The flanks which connect the horizontal line sections are notinteresting. The part of the screen of the cathode-ray tube whichdisplays the analog signals is preferably covered by a mask in such amanner that transparent vertical windows separated by opaque strips areobtained which permit of observation of the displayed signals, it beingpossible for each window to be provided with measuring scalescorresponding to the measuring values.

By extending the number of input channels of the oscilloscope, twofurther inputs may be utilized for applying limit values of themeasuring voltages. This is accomplished by using correspondingswitching members for connection to the upper and lower limit valuesassociated with each measuring signal.

These limit values indicate the values which are critical for themeasuring voltages and which may not be exceeded in normal cases. It ispossible to display evenly luminescing areas which areas extend from thelimits on either side above and below the measuring range instead oflimit values which are visible on the screen as horizontal lines so thatthe separation becomes much more conspicuous. For displaying these areasthe intensity of the electron beam may be reduced so that a cleardistinction of the measuring signal is still possible.

The operation of an oscilloscope which is provided with a cathode-raytube operating in accordance with the principle of vertical scanning forvisibly displaying signals is known in itself. The signal applied to aninput is compared in a comparator with a reference voltage synchronouslyincreasing with the vertical deflection voltage. As soon as the voltagesare equal a very short pulse is generated in the comparator and isapplied through an amplifier to the control grid of the cathoderay tubeproducing a voltage variation of sufficient magnitude for causing apreviously suppressed electron current to produce a light dot on thescreen. From the periodic comparison of the measuring voltage and theappplied voltage in the comparator in synchronisation with the verticaldeflection frequency, a series of timedependent pulses are generatedwhich succeed one another with equal intervals for a constant measuringsignal and are modulated in time for a measuring signal varyinginamplitude.

Therefore light impressions produced by the electron beam on the screenof the cathode-ray tube are in principle punctiform and the visibleobservation consists of a succession of punctiform impressions whichmerge into lines in case of sufficiently high frequency of the verticalscanning. In connection with the slow horizontal scanning, the use of ascreen having a persistence characteristic is desirable.

In order that the invention may be readily carried into effect it willnow be described in detail, by way of example, with reference to theaccompanying diagrammatic drawings, in which:

FIG. 1 shows the required electric circuit arrangement, and

FIG. 2 shows the screen of the cathode-ray tube divided by a mask into anumber of measuring fields.

The oscilloscope is indicated by the broken line 1 including the screen2 of the cathode-ray tube. The oscilloscope has four inputs 3, 4, 5 and6 each of which is connected to respective comparators 7, 8, 9 and 10. Apulse amplifier 11 serves for further handling of the electrical pulsesof these comparators which are applied to the control electrode (notshown) of the cathode-ray tube 2. Each of the comparators 7, 8,. 9 andis connected in a current circuit to the sawtooth generator 12 forvertical scanning. For the sake of simplicity, members for electrostaticbeam deflection are indicated. The use of electromagnetic deflection isalternatively possible.

Generally a comparator comprises a circuit whose output is controlled bythe input signals in synchronism with applied clock or timing pulses, anexample of which is found in US. Pat. No. 3,102,208. By applying to thecomparators a measuring voltage and a voltage which varies in the rhythmof the vertical scanning between a minimum and a maximum value, pulsevoltages arise at the outputs having a time sequence which is determinedby the values of the measuring voltages.

For a more detailed description of the device it is desirable, withreference to the analog voltages applied to the device, to distinguishbetween measuring voltages and limit value voltages. The electricvoltage directly derived from the physiologic phenomenon to be examinedis considered as the measuring voltage which is applied from therelevant measuring instrument to the device. The limit value voltagesare applied for bounding an area of permissible values of the measuringvoltage, and these may be separately adjustable. Therefore, for eachphysiologic unit, preferably a measuring voltage and two limit voltagesare available for the highest and the lowest measuring valuespermissible.

A number of these combinations of a measuring voltage and two limitvalue voltages is applied to contact series 13, 14 15 which permit, forexample, six connections each. The first second, third and followingpair of each contact series are simultaneously connected to an input ofthe device, and consequently the voltages then occurring are applied tothe comparators. The contact apertures may, for example, be shunted byso-called quick response magnetic reed relays, the magnetic energizingof which is controlled, for example, by a division scanner 16, in thiscase a six-division scanner which is adapted to apply the energizingcurrent successively through outputs 17 to corresponding relays in eachcontact series every time during one-sixteenth division of thehorizontal scanning period, for which purpose an input of the scanner isconnected to the horizontal time base 18. Broadly stated a divisionscanner comprises a chain of control relays and an electronic timingcircuit for generating tuning control pulses serving to trigger anelectronic counting circuit for developing a predetermined repeatingsequence of output signals which operate the control relays in apredetermined time relationship to the horizontal scanning period.Electronic switching elements may alternatively be used instead ofmagnetic switches. Consequently the device makes it possible during thehorizontal scanning to display successively 6 physiological measuringvoltages and the associated high and low limit values on the screen of acathode-ray tube. By suitable choice of the speed of the horizontalscanning in combination with the persistence characteristic of thescreen it may be achieved that the 6 physiological signals are visiblesimultaneously and continuously. A useful extension of the deviceconsists in that the pulses resulting from the limit value voltages areformed in such a manner that not only a highest and a lowest value areindicated but also adjoining strips extending upwards and downwardsrespectively may be made luminous on the display screen. To achieve thisa combination of electronically active components in a device 19 must beemployed for which the name of alarm logic" might be used. It contains,inter alia, a number of gating circuits which become conducting asregards the highest limit value due to a pulse received from theassociated comparator 9, and which return after a given period of timeto the original non-conducting condition. A further gating circuit maybe adjusted so as to be normally conductive and being reversed to anon-conducting condition by a pulse from the comparator 10 which marksthe lowest limit value, and remain in that condition until the beginningof a subsequent vertical scanning. An alarm circuit correspondinglyoperable for controlling magnitudes provided with means for scanning themagnitudes of a plurality of conditions and having for its object theprovision of signalling when a change occurs above or below apredetermined set value together with an indi cation of the fact thatthe aforesaid change has oc curred is shown in U. S. Pat. No. 3,234,532.

The complex of electrical pulses is applied to pulse amplifier 11 andsubsequently to the control electrode of the cathode-ray tube. In thedrawing the input 3 is destined for the supply of a dynamic signal whichis active during the entire horizontal time base, and the inputs 4, 5and 6 receive analog signals which are successively passed only duringpart of the time base.

In conformity therewith the upper part of the screen 2 of thecathode-ray tube is available for the dynamic signal throughout itswidth (electrocardiogram or pulse wave) after which the other partremains for analog signals. The lower part is covered by a mask 20 insuch a manner that 6 transparent vertical scales are obtained which areseparated by opaque strips. Measuring scales 21 may be provided on thetransparent parts.

To determine whether a measuring value exceeds the associated limitvalues, the device 19 includes in addition a combination of knownso-called logic" electronic circuits which, for example, determinewhether an electrical pulse received from comparator 8 falls or does notfall within the interval formed by the electrical pulses received fromthe comparators 9 and 10. When one of the limit values is exceeded theabove is no longer the case, and device 19 supplies an alarm signalwhich, for example, closes a relay contact in an internal or externalalarm current circuit. For signalling the alarm on the display screen,device 19 may apply one additional electrical pulse for verticalscanning in the case of alarm to the pulse amplifier 1 1 in such amanner that a luminescent alarm field appears on the display screen, forexample, in the space intended for the display of the dynamic signal.

It is possible to cause this alarm field, as viewed in a horizontaldirection, to appear only at the area where the relevant measuringsignal is also displayed. The device 19 may also comprise means forsupplying an acoustic signal when the limit value voltages are exceededby the measuring voltage.

What is claimed is:

l. A device for monitoring a plurality of parameters and displayingmeasuring voltages corresponding thereto on the screen of a cathode-raytube having a beam control electrode comprising, an oscilloscopeincluding said cathode-ray tube, a plurality of inputs and means forquick vertical scanning and for slow horizontal scanning of the displayscreen of the cathode-ray tube, means connecting at least one of theinputs of the oscilloscope to said beam control electrode and to anumber of switching members adapted to receive measuring voltagescorresponding to the monitored parameters, means synchronized with thehorizontal scanning means for sequentially operating said switchingmembers so as to successively connect the input to a number of measuringvoltages during mutually equal periods whereby each measuring voltage isconnected once to the relevant input during a horizontal scanning periodto vary the intensity of the cathode ray tube electron beam, and whereinthe oscilloscope includes two further inputs, a corresponding number ofswitching members connected to said two further inputs and adapted to beconnected to electric voltages which indicate a high and a low limitvalue of the respective measuring voltages, and wherein the latterswitching members are operated in synchronism with the former switchingmembers by said sequential operating means whereby the latter switchingmembers are successively connected to said limit voltages.

2. A device as claimed in claim 1 further comprising means responsive tosaid limit voltages for varying the intensity of the CRT electron beamso as to cause parts of the display screen of the cathode-ray tube toluminesce, which parts are located on either side of the measuring rangeenclosed by the limit values.

3. A device as claimed in claim 2 wherein the beam varying meanscomprises pulse extension circuits which are controlled by a limit valuevoltage.

4. A device as claimed in claim 1 further comprising circuit means forcoupling said switching members to the beam intensity control electrodeof the cathode ray tube, said circuit means including means fordisplaying the measuring voltage at a greater intensity than theintensity used for displaying the limit value voltages.

5. A device as claimed in claim 1 further comprising a device coupled tosaid switching members which includes means for producing an alarmindication when the measuring voltage exceeds one of the limit valuevoltages.

6. A device as claimed in claim 5 wherein the alarm producing meansincludes means coupled to the beam control electrode for producing alight spot on the display screen to provide the alarm indication.

7. A device as claimed in claim 1 further comprising a mask disposed onthe front side of the display screen and including vertical opaquesections arranged to separate the displayed measuring voltages.

8. A device as claimed in claim 1 further comprising first, second andthird signal comparison devices, means individually connecting a firstinput of said comparison devices to said three inputs of theoscilloscope, means connecting said vertical scanning means to a secondinput of each of said comparison devices, and means connecting an outputelectrode of each comparison device to the beam intensity controlelectrode of the cathode ray tube.

9. A device as claimed in claim 8 further comprising an alarm devicehaving an input coupled to the output electrodes of said first, secondand third comparison devices and an output electrode coupled to saidbeam control electrode to apply a voltage pulse thereto whenever themeasuring voltage exceeds the upper or lower values of the limitvoltages.

10. A device for monitoring a plurality of parameters and displayingmeasuring voltages corresponding thereto on the screen of a cathode-raytube having a beam control electrode comprising, an oscilloscopeincluding said cathode-ray tube, a plurality of inputs and means forquick vertical scanning and for slow horizontal scanning of the displayscreen of the cathode-ray tube, means connecting at least one of theinputs of the oscilloscope to said beam control electrode and to anumber of switching members adapted to receive measuring voltagescorresponding to the monitored parameters, means synchronized with thehorizontal scanning means for sequentially operating said switchingmembers so as to successively connect the input to a number of measuringvoltages during mutually equal periods whereby each measuring voltage isconnected once to the relevant input during a horizontal scanning periodto vary the intensity of the cathode ray tube electron beam, and saidconnecting means includes signal comparison means having first andsecond inputs coupled to said oscilloscope input and to said verticalscanning means, respectively, and an output coupled to the beamintensity control electrode of the cathode ray tube to apply a pulsetype signal thereto which unblanks the electron beam upon equality ofthe voltages appearing at said first and second inputs.

1. A device for monitoring a plurality of parameters and displayingmeasuring voltages corresponding thereto on the screen of a cathode-raytube having a beam control electrode comprising, an oscilloscopeincluding said cathode-ray tube, a plurality of inputs and means forquick vertical scanning and for slow horizontal scanning of the displayscreen of the cathode-ray tube, means connecting at least one of theinputs of the oscilloscope to said beam control electrode and to anumber of switching members adapted to receive measuring voltagescorresponding to the monitored parameters, means synchronized with thehorizontal scanning means for sequentially operating said switchingmembers so as to successively connect the input to a number of measuringvoltages during mutually equal periods whereby each measuring voltage isconnected once to the relevant input during a horizontal scanning periodto vary the intensity of the cathode ray tube electron beam, and whereinthe oscilloscope includes two further inputs, a corresponding number ofswitching members connected to said two further inputs and adapted to beconnected to electric voltages which indicate a high and a low limitvalue of the respective measuring voltages, and wherein the latterswitching members are operated in synchronism with the former switchingmembers by said sequential operating means whereby the latter switchingmembers are successively connected to said limit voltages.
 2. A deviceas claimed in claim 1 further comprising means responsive to said limitvoltages for varying the intensity of the CRT electron beam so as tocause parts of the display screen of the cathode-ray tube to luminesce,which parts are located on either side of the measuring range enclosedby the limit values.
 3. A device as claimed in claim 2 wherein the beamvarying means comprises pulse extension circuits which are controlled bya limit value voltage.
 4. A device as claimed in claim 1 furthercomprising circuit means for coupling said switching members to the beamintensity control electrode of the cathode ray tube, said circuit meansincluding means for displaying the measuring voltage at a greaterintensity than the intensity used for displaying the limit valuevoltages.
 5. A device as claimed in claim 1 further comprising a devicecoupled to said switching members which includes means for producing analarm indication when the measuring voltage exceeds one of the limitvalue voltages.
 6. A device as claimed in claim 5 wherein the alarmproducing means includes means coupled to the beam control electrode forproducing a light spot on the display screen to provide the alarmindication.
 7. A device as claimed in claim 1 further comprising a maskdisposed on the front side of the display screen and including verticalopaque sections arranged to separate the displayed measuring voltages.8. A device as claimed in claim 1 further comprising first, second andthird signal comparison devices, means individually connecting a firstinput of said comparison devices to said three inputs of theoscilloscope, means connecting said vertical scanning means to a secondinput of each of said comparison devices, and means connecting an outputelectrode of each comparison device to the beam intensity controlelectrode of the cathode ray tube.
 9. A device as claimed in claim 8further comprising an alarm device having an input coupled to the outputelectrodes of said first, second and third comparison devices and anoutput electrode coupled to said beam control electrode to apply avoltage pulse thereto whenever the measuring voltage exceeds the upperor lower values of the limit voltages.
 10. A device for monitoring aplurality of parameters and displaying measuring voltages correspondingthereto on the screen of a cathode-ray tube having a beam controlelectrode comprising, an oscilloscope including said cathode-ray tube, aplurality of inputs aNd means for quick vertical scanning and for slowhorizontal scanning of the display screen of the cathode-ray tube, meansconnecting at least one of the inputs of the oscilloscope to said beamcontrol electrode and to a number of switching members adapted toreceive measuring voltages corresponding to the monitored parameters,means synchronized with the horizontal scanning means for sequentiallyoperating said switching members so as to successively connect the inputto a number of measuring voltages during mutually equal periods wherebyeach measuring voltage is connected once to the relevant input during ahorizontal scanning period to vary the intensity of the cathode ray tubeelectron beam, and said connecting means includes signal comparisonmeans having first and second inputs coupled to said oscilloscope inputand to said vertical scanning means, respectively, and an output coupledto the beam intensity control electrode of the cathode ray tube to applya pulse type signal thereto which unblanks the electron beam uponequality of the voltages appearing at said first and second inputs.